1. Field of the Invention
The present disclosure relates to operation control apparatuses and operation control methods for an external apparatus connected to a vehicle-mounted apparatus. The present disclosure particularly relates to an art of controlling an operation on an external apparatus connected to a vehicle-mounted apparatus in accordance with an operation on a soft key displayed on a touch panel of the vehicle-mounted apparatus or a hard key provided in the vehicle-mounted apparatus.
2. Description of the Related Art
In recent years, technologies have been proposed that allow a function of an external apparatus to be used through a vehicle-mounted apparatus by connecting the external apparatus to the vehicle-mounted apparatus. For example, a technology has been proposed which allows a tune stored in a portable digital music player as an external apparatus to be played through a vehicle-mounted apparatus connected to the portable digital music player. Another technology has been proposed which connects a mobile terminal (what-is-called a smart phone) having both the functions of a cellular phone and the functions of a portable information terminal (PDA) to a vehicle-mounted apparatus to allow a function of an application installed in the smart phone to be used through the vehicle-mounted apparatus.
When a function of an external apparatus is used through a vehicle-mounted apparatus in this way, an operation in the external apparatus may be controlled from the vehicle-mounted apparatus. For example, in order to play a tune stored in an external apparatus through a vehicle-mounted apparatus, an operation for playing, starting or stopping or pausing the music may be controlled from the vehicle-mounted apparatus side. An instruction for the operation control may be issued by operating a hard key (such as a play button, a stop button, and a pause button) provided in the vehicle-mounted apparatus.
For example, when a play button in a vehicle-mounted apparatus is pressed, the vehicle-mounted apparatus transmits a play start command to an external apparatus. On the basis of the play start command transmitted from the vehicle-mounted apparatus, the external apparatus performs an operation for playing music. The reproduced sound data of the tune is transmitted to the vehicle-mounted apparatus, and the reproduced sound is output from a speaker of the vehicle-mounted apparatus. When a pause button in the vehicle-mounted apparatus is pressed during a music play operation, the vehicle-mounted apparatus transmits a pause command to the external apparatus. On the basis of the pause command transmitted from the vehicle-mounted apparatus, the external apparatus performs a music pause operation.
When soft keys such as play start, play stop, and pause are displayed on a display apparatus with a touch panel of a vehicle-mounted apparatus (hereinafter, simply called a touch panel), an operation control over an external apparatus may be instructed from the vehicle-mounted apparatus side by operating either hard key or soft key. Japanese Unexamined Patent Application Publication No. 2007-52643 discloses an art which includes a first mode for an operation by using a hard key and a second mode for an operation by using a soft key, wherein an operation on a soft key when the first mode is set and an operation on a hard key when the second mode is set are inhibited.
In order to display soft keys on a touch panel of a vehicle-mounted apparatus, image information including the soft keys may be transmitted from an external apparatus to the vehicle-mounted apparatus to display the image information on the touch panel. According to this method, the vehicle-mounted apparatus may not grasp the positions of soft keys on the touch panel. In other words, when one of the soft keys displayed on a touch panel is pressed, the vehicle-mounted apparatus may locate the pressed position but may not identify which soft key has been pressed. For that, the vehicle-mounted apparatus transmits pressed position information describing the pressed position to the external apparatus. The external apparatus identifies which soft key has been pressed on the basis of the pressed position information transmitted from the vehicle-mounted apparatus and performs an operation corresponding to the identified soft key.
It will be appreciated that, in order to save the space where hard keys are disposed, one button (play/pause button) may often be used as both of a play start button and a pause button in a vehicle-mounted apparatus. In this case, every time the play/pause button is pressed, play start and pause operations are performed alternately. On the basis of the change of the execution state, which operation of the operations associated with the play/pause button is acceptable is changed alternately.
In other words, in an initial state, the play/pause button in the vehicle-mounted apparatus may accept a play start command. When the play/pause button is pressed in this state, music is started to play in the external apparatus, and the play/pause button shifts to a state in which a pause command is acceptable. When the play/pause button is pressed in this state, the play of music in the external apparatus is paused. The play/pause button shifts to a play start acceptable state. After this, every time the play/pause button is pressed, these operations are repeated.
Regarding soft keys displayed on a touch panel of a vehicle-mounted apparatus, the displays of a play button and a pause button may be switched alternately at one position in many cases in order to save the display space of the soft keys. In other words, in an initial state, a play button is displayed. When the play button is pressed, music starts to play, and a pause button is displayed instead of the play button. When the pause button is pressed in this state, the music playback is paused in the external apparatus, and the play button is displayed instead of the pause button. After this, every time the play button and pause button are pressed, these operations are repeated.
As described above, when soft keys are displayed on a touch panel of a vehicle-mounted apparatus, an operation control over an external apparatus may be instructed from the vehicle-mounted apparatus side by operating either hard key or soft key. However, when image information including soft keys is transmitted from the external apparatus to the vehicle-mounted apparatus including a play/pause button as hard keys to display the soft keys on the touch panel, a malfunction, as will be described below, may occur.
FIGS. 11A to 11C are diagrams for illustrating conventional malfunctions. FIG. 11A illustrates a state where music is being played as a result of press of a play/pause button 11 in a vehicle-mounted apparatus. In this case, the play/pause button 11 as a hard key is a pause acceptable state. A pause button 12 is displayed as one of soft keys on the touch panel. In other words, when an external apparatus receives a play start command from a vehicle-mounted apparatus, an external apparatus generates image information including the pause button 12. As a result of transmission of the image information from the external apparatus to the vehicle-mounted apparatus, the pause button 12 is displayed.
When the pause button 12 of the soft keys is pressed in this state, the vehicle-mounted apparatus transmits pressed position information describing the pressed position to the external apparatus. The external apparatus determines that the pause button 12 has been pressed on the basis of the pressed position information transmitted from the vehicle-mounted apparatus and executes a pause operation. The external apparatus further generates image information including a play button 13 as one of the soft keys and transmits the image information to the vehicle-mounted apparatus. FIG. 11B illustrates a state where the image information transmitted from the external apparatus is displayed on the touch panel of the vehicle-mounted apparatus. In other words, the touch panel displays the play button 13 as one of the soft keys instead of the pause button 12.
While music is paused as illustrated in FIG. 11B, the play button 13 is properly displayed as a soft key while the play/pause button 11 as a hard key still has the pause acceptable state. Even when the pause button 12 on the touch panel is pressed in the state in FIG. 11A, the vehicle-mounted apparatus is only allowed to grasp the pressed position but is not allowed to securely determine that the pause button 12 has been pressed.
Therefore, when the play/pause button 11 is pressed in the pause state as illustrated in FIG. 11B, a pause command is transmitted from the vehicle-mounted apparatus to the external apparatus though it has already been in the pause state. In this case, an error occurs that the operational state does not change even though the play/pause button 11 is pressed. In other words, even though a user presses the play/pause button 11 to restart playing music, the pause state is maintained such that music does not begin to play and the display of the soft key does not change such that the play button 13 is still displayed, as illustrated in FIG. 11C.
This problem is not limited to the case where one play/pause button 11 is used for switching between a play start function and a pause function. For example, the same problem may occur in cases where a plurality of functions are assigned to one hard key, and the hard key is used to switch between the corresponding operations every time the hard key is pressed, such as a case where one mute button is used for switching a mute function on and off or a case where one power button is used to switch a power supply on and off.